I think you want to display the image from your Inspiron 6400 on a TV and I think that you have connected a cable to the S-video socket of the Inspiron 6400. Please advise the type of input that you want to use on the TV (Note: the easiest type of input to use on the TV is an S-video input). Please also advise details of the cable that you are trying to use.
This is how you enable the Display Settings for a TV.
NOTE: To ensure that the display options appear correctly, connect the TV to the computer before you enable the display settings.
1. Click the Start button, point to Settings, and then click Control Panel.
2. Double-click Display and click the Settings tab.
3. Click Advanced.
4. Click the tab for your video card.
NOTE: To determine the type of video card installed in your computer, see the Windows Help and Support Center. To access the Help and Support Center, click Start Help and Support. Under Pick a Task, click Use Tools to view your computer information and diagnose problems. Then, under My Computer Information, select Hardware.
5. In the display devices section, select the appropriate option for using either a single display or multiple displays, ensuring that the display settings are correct for your selection.
You need a component video adapter cable that is compatible with your Inspiron 6400. The Dell S-video to TV-component cable at this link <ADMIN NOTE: Broken link has been removed / replaced from this post by Dell> should be suitable, however if you order it you must confirm with Dell that it is compatible with the Inspiron 6400 as well as the XPS M1710 laptop.